topic Re: Xgen Tilt U V (misaligned faces?) in Maya Dynamics Forum

Xgen Tilt U V (misaligned faces?)

dangertaz1 — Fri, 19 May 2017 03:57:33 GMT

In Xgen, when I use custom geometry or cars. I need them to lay along my geometry (like feathers). Sometimes Tilt U or V works for this. Sometimes my archived geometry or cards will point in different directions as shown on the car model below: Some of the cards lay across car and some lay along the length of the car. Even though the Tilt V is the only attribute driving them. Normals are correct on all faces...thoughts?

Re: Xgen Tilt U V (misaligned faces?)

Michael_Todd — Fri, 19 May 2017 19:05:48 GMT

When using attributes to drive XGen parameters like tilt, the construction winding order of the underlying geometry's faces determines the vector used, and this can change across the surface as some faces can be left handed and some can be right.

Sometimes changing the point ordering can help but usually the simplest way to get a uniform, controlled direction is to use groomable splines and use the brushes to control the direction of the splines

Re: Xgen Tilt U V (misaligned faces?)

dangertaz1 — Sat, 20 May 2017 15:55:55 GMT

Please correct me if I'm wrong, but a spline is a spline and custom geo is custom geo.

Splines can be groomed, but custom geo cannot be groomed.

Unless I'm unaware of something, I need to use guides to really control the orientation of custom geo?

At the moment, I'm duplicating my description and applying to the faces that are misbehaving. I adjust the Tilt V to a different number to make my feathers lay down correctly on these particular faces.

Re: Xgen Tilt U V (misaligned faces?)

mspeer — Sat, 20 May 2017 18:41:52 GMT

Hi!

It's not that easy.

The following with Quad Draw Tool will lead to 2 different results (directions/orientation).

("Reorder Vertices" made it more worse in my tests, so don't expect it to help.)

Re: Xgen Tilt U V (misaligned faces?)

Michael_Todd — Wed, 24 May 2017 18:06:16 GMT

NO, the underlying winding order of the faces that Seexpr and ptex uses to evaluate the U and V directions is not easy to address in the mesh, but you paint maps with groomable splines and switch primitive types

Groomable Splines:

Cards

Re: Xgen Tilt U V (misaligned faces?)

mspeer — Wed, 24 May 2017 19:39:41 GMT

Hi!

@Michael_Todd , sorry i was not clear with my response.

This was not meant as a solution but more to give an idea that there is more than just the Vertex Position and the Normals that has influence on the final structure. Maybe it was not the best way to show this.

Re: Xgen Tilt U V (misaligned faces?)

Michael_Todd — Wed, 24 May 2017 20:37:54 GMT

I know, that's why I showed that you can use the groomable splines to paint maps that can be used to drive tilt U and V and have those maps drive other primitive types.

Seexpr and ptex are very particular when it comes to topology.

Re: Xgen Tilt U V (misaligned faces?)

dangertaz1 — Sat, 03 Jun 2017 04:17:13 GMT

I have tried grooming the splines with the orientation brush. The splines look perfect across all faces. I switch them to archives and they are still misaligned. I am attaching a simple scene which shows this. Is there a step I am missing?

Re: Xgen Tilt U V (misaligned faces?)

mspeer — Sat, 03 Jun 2017 07:56:13 GMT

Hi!

Set Tilt to 0.

Re: Xgen Tilt U V (misaligned faces?)

dangertaz1 — Mon, 05 Jun 2017 23:21:46 GMT

I have set the tilt to zero. I still have the issue. Imagine adding scales to a fish. The scales should remain parallel with each other across multiple faces. I believe I am following the suggested workflow by substituting groom-able splines and switching to my archive. My archive doesn't seem to care about the orientation of the the previous splines. Please watch the screencast.....maybe I forgot a step?

Re: Xgen Tilt U V (misaligned faces?)

Michael_Todd — Tue, 06 Jun 2017 19:14:54 GMT

It's important to keep in mind the orientation of the object to be exported as an archive. To have it align correctly in XGen, it needs to be aligned in the original scene, with it's pivot at a good location for it to be transformed around as an archive object.

In this video, I aligned this feather along Y so that it aligns with the tilt values in the maps derived from the groomable splines:

Make sure to freeze transforms on the object before exporting an archive. Any transforms will cause offsets of the object in the XGen scene. I notice that in your screengrab above, you're not using the maps from the groomable spline description to drive the parameters of the objects. This is why you're still seeing the flipping of the objects on different faces.

I set the width to 1 to override the width value from the splines but you might want to use the width from the maps to create variation (you can edit the expression to add a multiplier or random values or both)

Cheers

Re: Xgen Tilt U V (misaligned faces?)

dangertaz1 — Wed, 07 Jun 2017 02:56:30 GMT

Thank you so much for the screencast! I am solved

Re: Xgen Tilt U V (misaligned faces?)

Anonymous — Thu, 07 Dec 2017 18:10:40 GMT

thnku my problem solve too

Re: Xgen Tilt U V (misaligned faces?)

Anonymous — Sat, 27 Jan 2018 16:13:30 GMT

after using the the same method i still facing orientation problem, and they not are following direction